Endoscope and endoscopic system

Abstract

Disclosed is an endoscope including: a four-color separation prism configured to separate light from an object into three primary colors of light and infrared light; four image sensors configured to convert optical images of the separated three primary colors of light and an optical image of the separated infrared light into electrical signals; and an output device configured to output the converted electrical signals.

The invention claimed is: 
     
       1. An endoscope prism comprising:
 a four-color separation prism comprising a first color separation prism, a second color separation prism, a third color separation prism and a fourth color separation prism, the third color separation prism including a light incident surface which, in operation, reflects a third component of the light from an object, the light incident surface of the third color separation prism being adjacent a light reflective surface of the second color separation prism, 
 wherein the light incident surface of the third color separation prism is coextensive with the light reflective surface of the second color separation prism, and the light incident surface of the second color separation prism is adjacent a light reflective surface of the first color separation prism, 
 wherein one of the first color separation prism, the second color separation prism, the third color separation prism and the fourth color separation prism is an infrared prism. 
 
     
     
       2. The endoscope prism of  claim 1 , wherein the infrared separation prism is closest to a distal end of the endoscope. 
     
     
       3. The endoscope prism of  claim 1 , wherein the light reflective surface of the second color separation prism, in operation, reflects a second component of the light from an object. 
     
     
       4. The endoscope prism of  claim 3 , wherein the first color separation prism includes a light incident surface,
 the light reflective surface of the second color separation prism arranged relative to the light incident surface of the first color separation prism such that a first angle is formed between the light incident surface of the first color separation prism and the light reflective surface of the second color separation prism, and 
 the third color separation prism includes a light reflective surface arranged relative to the light incident surface of the first color separation prism such that a second angle is formed between the light incident surface of the first color separation prism and the light reflective surface of the third color separation prism, the first angle being less than the second angle. 
 
     
     
       5. The endoscope prism of  claim 4 , wherein the light reflective surface of the first color separation prism is arranged relative to the light incident surface of the first color separation prism such that a third angle is formed between the light incident surface of the first color separation prism and the light reflective surface of the first color separation prism, the first angle being less than the third angle. 
     
     
       6. The endoscope prism of  claim 1 , wherein the light reflective surface of the second color separation prism, in operation, reflects a fourth component of the light from an object. 
     
     
       7. The endoscope prism of  claim 6 , wherein the first color separation prism includes a light incident surface,
 the light reflective surface of the second color separation prism arranged relative to the light incident surface of the first color separation prism such that a first angle is formed between the light incident surface of the first color separation prism and the light reflective surface of the second color separation prism, and 
 the third color separation prism includes a light reflective surface arranged relative to the light incident surface of the first color separation prism such that a second angle is formed between the light incident surface of the first color separation prism and the light reflective surface of the third color separation prism, the first angle being less than the second angle. 
 
     
     
       8. The endoscope prism of  claim 7 , wherein the light reflective surface of the first color separation prism is arranged relative to the light incident surface of the first color separation prism such that a third angle is formed between the light incident surface of the first color separation prism and the light reflective surface of the first color separation prism, the first angle being less than the third angle.